抄録
Nitrogen use efficiency (NUE) in wheat arises from coordinated phenotypic plasticity and nitrogen-responsive regulation, yet the links between multidimensional plant traits and their molecular basis remain insufficiently resolved. Here, twenty genetically diverse wheat (Triticum aestivum L.) genotypes were evaluated across contrasting nitrogen supplies using a hydroponic system, and an integrated NUE assessment framework was developed by combining seedling morphological and physiological traits with multivariate statistical analyses. Root system architecture and biomass allocation emerged as key phenotypic determinants of NUE, revealing distinct genotype-specific strategies for nitrogen acquisition and utilization. The integrated framework reduced trait redundancy, differentiated NUE performance across genotypes, and identified four contrasting NUE response types, providing a multidimensional basis for germplasm classification. Molecular validation further showed that the candidate gene TaSPX1 displayed distinct nitrogen-responsive expression patterns associated with NUE variation, particularly through coordinated responses to nitrogen limitation and excess, suggesting a potential role in linking nitrogen signaling with root adaptation and resource allocation. Collectively, this study establishes a phenotype–classification–molecular validation framework that connects plant-level NUE variation with candidate regulatory responses, providing a mechanistic basis for identifying nitrogen-efficient germplasm and guiding precision breeding for sustainable wheat production.
